* Stronger typing for http errors with Rust client. (#5609).
* Error structure can be parametrized (but is still hardcoded with `serde_json::Value` in generated code).
* Each API method has is own enum of functionnal errors.
* Fix the missing "Debug" derivation for API error enums.
* Generate models for error deserialization.
* Handle several 2xx success models.
* Expose new API objects, required to use the API (params, success, error structs/enums).
Co-authored-by: William Cheng <wing328hk@gmail.com>